1. Field of the Invention
The present invention relates to a mass spectrometric method and a mass spectrometric system. Also, the present invention relates to a diagnosis system and an inspection system each using the mass spectrometric system, and to a mass spectrometric program.
2. Description of the Related Art
Mass spectrometry is divided into a method of performing mass analysis just after ionizing a sample (MS method), and a tandem mass spectrometric method of selecting a particular sample ion (parent ion) in terms of mass, and then performing mass analysis of dissociated ions produced by dissociating the selected sample ion. The tandem mass spectrometric method has the function of performing the dissociation process and the mass analysis in multiple stages (n-stage mass analysis; referred to as “MSn” hereinafter), i.e., the function of selecting, from among dissociated ions, an ion having a particular mass-charge ratio (precursor ion), further dissociating the precursor ion, and performing mass analysis of dissociated ions produced from the precursor ion.
A system in combination of a chromatograph and a mass spectrometer is used for quantitative analysis of a substance being present in very small amount and containing many impurities. In such a system, a substance to be quantitatively analyzed is first separated into components in terms of time by the chromatograph based on, e.g., differences in adsorption of the substance components to a column, and is then separated in terms of mass by the mass spectrometer. In the case of analyzing compounds having combinations of, e.g., isomers of sugar chains or two amino acids having the same mass as one certain amino acid, it is difficult to separate those compounds in terms of mass, but most of the compounds can be separated in terms of time by chromatography based on their chemical and physical properties.
Identification of peptides and proteins is usually carried out by a method using a database search or a method reading an amino acid sequence from the peak intervals of mass spectrum data. Those methods are each executed as post-processing. Therefore, if the amount of information regarding the obtained spectrum is insufficient, the mass spectrum data has to be taken again. Because of a difficulty in repeating the measurement, therefore, those known methods are not useful for analysis of a very small amount of sample, e.g., morbid protein.
JP,A 2000-266737 (Patent Document 1) discloses a method of analyzing a measurement target by comparing the retention time in a sample separating section and the mass spectrum data, which are obtained for the measurement target, with the data of known substances. However, a series of data processing is executed as post-processing.